These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: Higher pollinator effectiveness by specialist than generalist flower-visitors of unspecialized Knautia arvensis (Dipsacaceae).
    Author: Larsson M.
    Journal: Oecologia; 2005 Dec; 146(3):394-403. PubMed ID: 16133196.
    Abstract:
    A critical issue in pollination ecology is the evolution of generalist pollination systems, and under which conditions floral specializations evolve from these. The gynodioecious herb Knautia arvensis (Dipsacaceae) exhibits a generalized pollination system, but is visited by both generalist and specialist flower-visitors. The present study tested pollinator effectiveness and pollinator importance of the pollen specialist solitary bee Andrena hattorfiana (Andrenidae) vs. the generalist flower-visitors to K. arvensis on the island of Oland, SE Sweden. Females of the specialist bee removed more pollen per inflorescence-visit than the major groups of generalist visitors such as bumblebees and flies. They also deposited more pollen per inflorescence-visit than any of the generalist visitor groups. The females have a preference for pollen-presenting vs. stigma-presenting inflorescences, a pattern shared with most of the generalist flower-visitors. Females of the specialist exert such a strong preference that they, despite their great pollinator effectiveness, make modest contribution to pollen transfer in K. arvensis. The females of A. hattorfiana accounted for 14.2% of the overall visits and 5.8% of the total pollination, the rest being performed by generalist visitors and males of A. hattorfiana. This study shows that pollinator effectiveness of a specialist can be superior while generalist flower-visitors select floral characters towards generalization through their greater contribution to overall pollen flow.
    [Abstract] [Full Text] [Related] [New Search]